1. Field of the Invention
The present invention relates to an image processing apparatus that displays a list of items, a control method thereof, and a storage medium storing a program.
2. Description of the Related Art
With conventional multifunction peripherals (hereinafter, MFPs), when displaying a list screen showing, for example, thumbnail images or a list on a manipulation unit, if there are items that do not fit to the single screen, such items that are not displayed are viewed by a user pressing a page turn button, a scroll button or the like. In contrast, recently, there are some mobile devices that allow users to perform a slide manipulation (gesture manipulation) on a list screen that displays a list. The slide manipulation is an operation that implements ease of manipulation by users that is intuitive by expressing a list screen on the manipulation screen as if physically present. Specifically, the user can regard the list screen as a physical medium such as paper, and touch the list screen with his/her finger so as to move what is displayed, and then lift the finger from the screen. The velocity at the time when the user lifts the finger is set as the initial velocity, and while its velocity and direction are maintained according to the law of inertia, which is one of the laws of physics, the screen is slid by deceleration due to virtual friction and eventually the slide stops.
However, in reality, the items displayed on the list screen are those that are dynamically changed, which is different from the case where physical media are handled. With respect to the slide manipulation on the list screen implemented with mobile devices, Japanese Patent Laid-Open No. 2011-530738 takes the following two approaches to such items that are dynamically changed:
(1) items displayed on a list screen are dynamically changed while being slid; and
(2) cached items are kept displayed and no dynamic change is displayed until the content of a changed item is re-acquired.
This is because the items displayed on the list screen of mobile devices are mostly those (an address book, a storage document, and the like) that are not changed without manipulation by the user, and thus importance is not placed on a dynamic change of displayed items.
However, with MFPs, how to notify the user of such a dynamic change of the items is important. For example, if the items regarding the job status displayed on the list screen are not updated and thus not new, the user who came to the MFP so as to check when a print job input by the user is to be executed cannot notice, even if the print job has been completed, that fact. In this case, a situation may occur in which the printed product printed by the print job is slipped into other printed products and taken away by somebody else. Alternatively, a situation may occur in which when sending a facsimile or the like, the user cannot find the transmission job that the user wants to stop, and the facsimile is sent.
In order to avoid such problems, with a conventional MFP, such a change in the items displayed on the list screen is detected by the fact that the page turn button or a screen update button has been pressed by the user, or by the fact that a poll or event has been received. Then, latest information is acquired at that timing, and the content displayed on the list screen is updated.
Problems that arise in the above example will be described below.
The user who came to the MFP so as to check when a print job input by the user is to be executed flicks the list screen showing the job execution status so as to perform slide display. At this time, with this slide display, the items displayed on the list screen are sequentially slid and displayed in the display area, but the finished jobs disappear from the items displayed on the list screen showing the job status.
As in (1) mentioned above, when the items displayed on the list screen are dynamically changed by sliding, the displayed items are slid and then disappear. In this case, the user simultaneously sees both changes due to the displayed items being slid by flicking and changes in the displayed items due to changes in jobs. This causes a problem in that it is very difficult for the user to check the displayed items, and the user may not notice a change in the jobs.
In the case of (2) mentioned above, the items displayed on the list screen are not dynamically changed, and thus the user cannot notice an actual change of the job status.
As described above, in the case where the conventional technique for mobile devices is applied to MFPs, problems arise such as even if a change occurs in the displayed items during slide operation on the list screen, the displayed items are not updated to latest ones. Alternatively, if many changes occur in the displayed items, the user cannot notice the changes in the displayed items.